The present invention relates to electronic chance devices, and more specifically to video poker devices.
Video poker devices are a significant source of revenue for casinos, and casinos continue to search for new ways to attract players to such devices. Like most gaming devices, video poker devices allow players to wager on various game outcomes. A typical video poker device receives a wager amount from a player and generates an initial hand of five cards that are drawn from a xe2x80x9cdeckxe2x80x9d of fifty-two different cards. Each card has a suit (clubs, spades, hearts or diamonds) and a rank (2-10, Jack, Queen, King, or Ace).
The player then selects which cards, if any, he would like to xe2x80x9choldxe2x80x9d. The player may hold anywhere from no cards to all five cards. Cards that are not held are discarded (removed from the initial hand) and replaced with an equal number of new cards that are drawn from the deck of forty-seven remaining cards (52xe2x88x925=47).
The cards that are selected to be held define a xe2x80x9cdraw strategyxe2x80x9d. For example, if the first and third cards are held, then the corresponding draw strategy is to discard the second, fourth and fifth cards and draw three new cards to replace them. After new cards are drawn, a second hand (also called a xe2x80x9cfinal handxe2x80x9d) results. The second hand is different from the initial hand unless all five cards are held (no cards are drawn). Since each of the five cards in the hand may either be held or not held (i.e. two choices per card), each initial hand defines thirty-two draw strategies (2*2*2*2*2=32). Similarly, each draw strategy defines a set of possible second hands. For example, if the draw strategy is to hold the first four cards (draw one card to replace the fifth), then that draw strategy defines forty-seven possible second hands (the one card drawn may be one of forty-seven cards in the deck). Each of these forty-seven possible second hands includes the first four cards of the initial hand, and also includes a fifth card that is selected from the deck. In another example, if the draw strategy is to hold all cards (draw no cards), then that draw strategy defines one possible second hand, the initial hand.
If the second hand is a type of xe2x80x9cwinning handxe2x80x9d, the player is awarded a payment amount that is based on the winning hand and the wager amount. A xe2x80x9chand groupingxe2x80x9d defines one or more winning hands that share a characteristic. For example, the hand grouping xe2x80x9cfour of a kindxe2x80x9d, defines several winning hands, each of which has four cards of the same rank. The following three winning hands are included in the set defined by the hand grouping xe2x80x9cfour of a kindxe2x80x9d:
J-hearts, J-diamonds, J-clubs, J-spades, 7-clubs
7-clubs, 8-hearts, 8-diamonds, 8-clubs, 8-spades
J-hearts, J-diamonds, 3-diamonds, J-clubs, J-spades
Similarly, the hand grouping xe2x80x9croyal flushxe2x80x9d defines four winning hands:
10-hearts, Jack-hearts, King-hearts, Queen-hearts, Ace-hearts
10-diamonds, Jack-diamonds, King-diamonds, Queen-diamonds, Ace-diamonds
10-spades, Jack-spades, King-spades, Queen-spades, Ace-spades
10-clubs, Jack-clubs, King-clubs, Queen-clubs, Ace-clubs
In video poker, the arrangement of the cards within a hand is ignored. Some hand groupings are mutually exclusive. Thus, a hand included in one such hand grouping cannot be included in another such hand grouping. For example, a hand:
10-diamonds, Jack-diamonds, King-diamonds, Queen-diamonds, Ace-diamonds
is included in the set defined by xe2x80x9croyal flushxe2x80x9d, but not in the set defined by xe2x80x9cflushxe2x80x9d.
Typically, each hand grouping has a corresponding payout ratio that defines an amount of payment won for each unit of a wager amount. If the second hand is a winning hand, then the hand grouping corresponding to that hand indicates a payout ratio, and the payout ratio multiplied by the wager amount is the payment awarded. For example, if the second hand is:
Ace-hearts, 3-hearts, 7-hearts, 5-hearts, 10-hearts
then the corresponding hand grouping is a xe2x80x9cflushxe2x80x9d(all cards have the same suit). If xe2x80x9cflushxe2x80x9d has a corresponding payout ratio of six, then the payment amount is six times the wager amount.
Each draw strategy has an expected value which generally indicates the average payout that will be received if a draw strategy is chosen for a first hand. The expected value of a draw strategy may be calculated as the sum of the products of the probability of receiving each possible second hand times the payment amount won (if any) for receiving each possible second hand. The optimum draw strategy is the draw strategy having the highest expected value.
For example, a player dealt a first hand of
King-diamonds, King-spades, 8-hearts, 8-clubs, 2-clubs
may select the draw strategy of holding the two Kings and the two 8""s, and discarding the 2-clubs. Consequently, only two hand groupings are possible: a full house (three cards with one rank and two cards with another rank) or two pair. The expected value of this draw strategy is the sum of the products of the probability of each hand grouping occurring multiplied by the payment received according to each hand grouping.
For the selected draw strategy, the second hand will be a xe2x80x9cFull housexe2x80x9d if the drawn card is a King or an 8, and two kings and two 8""s remain in the deck of forty seven cards. Accordingly, the probability of a xe2x80x9cFull Housexe2x80x9d is approximately 8.5% (4/47=0.085). Similarly, if any of the other cards are drawn from the deck, the second hand will be xe2x80x9cTwo Pairxe2x80x9d. Accordingly, the probability of xe2x80x9cTwo Pairxe2x80x9d is approximately 91.5% (43/47=0.915).
If the payout ratio for a xe2x80x9cFull Housexe2x80x9d is xe2x80x9c9xe2x80x9d and the payout ratio for two pair is xe2x80x9c2xe2x80x9d, the expected value of the selected draw strategy may be calculated as follows:
[0.085*9]+[0.915*2]=[0.766]+[1.83]=2.596 
Professional video poker players can often or always choose xe2x80x9coptimumxe2x80x9d draw strategies for each initial hand. Thus, professional players generally tend to win somewhat higher average payment amounts from video poker devices than less skilled, nonprofessional players do. These nonprofessional players most often follow suboptimum strategies, and so the gaming device must maintain relatively high payout ratios in order to provide nonprofessional players with some benefit for playing. Professional players can take advantage of these high payout ratios to win significant amounts of money.
Since professional players win more payment amounts than nonprofessional players typically win, casinos face pressures from two directions. On one hand, they would like to reduce the payout ratios so professional players will not occupy the machine for hours, since such play typically results in little profit for the casino or even a loss. On the other hand, nonprofessional players receive lower payments on average than professional players, and so reducing the payout ratios would be unfair to nonprofessional players and might discourage them from playing.
U.S. Pat. No. 5,511,781 to Wood et al. describes a game system that calculates the expected value of elements (e.g. cards) a player currently possesses. The expected value is used to set the size of a guaranteed award provided if the player stops playing.
U.S. Pat. No. 5,401,023 to Wood describes a video poker game that calculates the optimum strategy from the expected value of each possible strategy. The video poker game computes the expected value of each discard strategy and then determines which discard strategy is the optimum strategy. If the player selects a strategy other than the optimum strategy, the award values for the hand groupings of cards are adjusted so the expected value of the selected strategy is substantially equal to that of the optimum strategy. Thus, players who are not able to recognize what constitutes the optimum strategy for any given hand will win substantially the same amount of money over a long term as more skilled players who can recognize and play the optimum strategy for any given hand. The game displays the adjusted awards to the player after each strategy is selected. This permits the player to evaluate the possible strategies.
The above-described patents do not address the problems caused by professional players. On the contrary, in U.S. Pat. No. 5,401,023 all players tend to win substantially the same amount of money over a long term. Thus, casinos would have to lower the payout ratios in order to make comparable profits, thus discouraging players who seek higher payment potential.
In addition, many players may have been attracted to video poker because of the increased payment resulting from analytical thought and decision making. However, as their experience increases and they become comfortable implementing the optimum strategies, the game appears stagnant and conventional. Thus, many players that often choose optimum draw strategies are bored with video poker and do not play as often or as much as they would if the game were more interesting.
It would be advantageous to provide a method and apparatus that reduced or eliminated the above-cited drawbacks of the prior art.
It is an object of the present invention to increase a player""s attraction to a video poker device.
In accordance with the present invention, a gaming device generates an initial hand of five cards. The first hand defines thirty-two draw strategies (each card held or not held), and at least one draw strategy is an optimum draw strategy having the maximum expected value of all draw strategies. The gaming device then selects a hand grouping that cannot result from the optimum draw strategy. For example, for an initial hand xe2x80x9c10-clubs, 10-spades, 5-diamonds, 2-diamonds, 4-diamondsxe2x80x9d, the hand grouping xe2x80x9cFlushxe2x80x9d cannot result from a draw strategy that requires holding two or more cards with different suits.
The payout ratio of the selected hand grouping is increased by adding a bonus amount thereto. The gaming device thus provides an incentive for a player to select a suboptimum draw strategy, yet the expected value of the optimum strategy is unaffected by the increased payout.